Apparatus for controlling temperature fluctuations.



J. E. HEDIN.

APPARATUS FOR CONTROLLING TEMPERATUREFLUGTUATIONS.

APPLIOATION FILED AUG. 5, 1908.

949,825. Patented Feb. 22, 1910.

- JOHN ERIK HEDIN, 0F LIDKGPING, SWEDEN.

APPARATUS FOR CONTROLLING TEMPERATURE FLUCTUATIONS.

Specification of Letters Patent. I

Patented Feb. 22, 1910.

Application filed August 5, 1908. Serial No. 447,146.

To all whom it may concern:

Be it known that I, JOHN ERIK HEDIN, a

subject of the King of Sweden, and residing at Lidkoping, Sweden, have invented certain new and useful Improvements in Apparatus for Controlling Temperature Fluctuations; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form. a part of this specification.

The present invention relates to an apparatus for indicating temperature fluctuations of such kind as are provided with two spirally wound wires, or bands, which on account of their being heated to different temperatures will change their shape, whereby two contacts of an electric circuit are finally pressed against each other so as to give a signal, for instance-an alarm.

The invention consists therein, that the,

spirals are adj ustably arranged, for instance, that their inner ends are arranged on adjustable parts, for example screws or pins, in order that the free ends of said spirals, being provided with the contacts, may be adjusted in relation to each other only by turning the screws or pins whereon the spirals are arranged.

A constructional form of the invention is shown on the drawing, where- Figure 1 is a plan view and Fig. 2 a sectional view on line AB in Fig. 1. I

The bands (1 and b consist of two different materials, having different coefiicients of dilatation, whereby they will alter their shape considerably, when the temperature rises or falls a very small amount. The band a is inclosed in a shell of a material, which to a certain degree is an insulator for the heat, while the other band I) is fully exposed to the heat. The band a is inclosed in the shell c, which is provided with a cover 0 and secured to apin cl projecting from the bottom of the shell 0, while the band 6 is arranged outside the shell and secured to a pin 6, projecting from the cover 0 of the shell. Thespiral b is suitably surrounded by a net work 7 or such like. One of the spirals or its pin is connected with the one pole of an electric source and the other spiral or its pin with the other pole and in one of the said connections an alarm device,

for instance an. electric bell, is arranged. The end of the spiral a or a contact g secured thereto, projects outside the shell 0 through an opening it in the coverthereof, whereby the said contact 9 will finally abut against the other spiral b or a contact 11 thereon, when the spiral ends move relatively to each other.

The apparatus works in the following way :When the temperature rises rapidly, the outer spiral b will be heated more rapidly than the spiral a inclosed in the insulating shell 0, whereby the contact 11 on account of the dilatation and the greater change of the shape of the spiral b, will abut against the contact 9, whereby the circuit will be closed. when the temperature rises slowly, both the spirals will change their shape in the same way, but finally the contact 9 will abut against the edge of the opening h, whereby the other contact 2' will finally in its continued motion abut against it so that the circuit will be closed. The spirals can also be arranged in such a way, that the two contacts'g and '2' normally abut against each other and are separated from each other when the spirals are heated. On account thereof, that the pins 03 and e are adjustable, the apparatus may be made more or less sensitive, as the distance between the two contacts 9 and i as well as the distance between 9 and the edge of the opening it may be altered.

A very important feature with the new apparatus is that the outer ends of the spirals are quite free and not connected with other parts, which makes it possible to make the bands, wires or the like very thin in order to augment their sensibility.

It is clear, that the apparatus may be used for indicating as well when the temperature falls as when it rises.

What I claim is 1. An apparatus for indicating temperature fluctuations, comprising a casing haying a slot therein, a coiled spring in said casing having its inner end secured to the casing and its outer end free, and a portion on its outer end extending through said slot,

at second coiled spring mounted on the casing and having its inner end secured thereto and its outer end free, a pro ecting portion on the outer end of said second coiled spring adapted to contact with the projecting portion on the first spring, and electric indicating means connected to said springs.

2. An apparatus for indicating temperature fluctuations, comprising a casing, an adjustable pin mounted therein, a coiled spring having its inner end secured to said pin and its outer end free, and a projecting portion on its outer end, said casing having a slot therein through Which the projecting portion passes, a second adjustable pin mounted on the top of the casing, a second coiled spring having its inner end secured to said pin and its outer end free, and having a projecting portion on its outer end adapted to contact with the projecting portion on the first spring, and an electric circuit connected to said pins.

In testimony, that I claim the foregoing as my invention, I have signed my name in presence of two subscribing Witnesses.

JOHN ERIK HEDIN.

Witnesses HARRY ALBILM, Y. L. KJELLBERG. 

